The Dark Angels are a Chapter of Space Marines in Warhammer 40,000. They were the first legion of Space Marines. Their homeworld was Caliban, where their Primarch, Lion El'Jonson, grew up. However, half their number rebelled following the Horus Heresy, and they ruthlessly hunt these "Fallen Angels" while keeping the Fallen's existence secret.They feature in the novel Angels of Darkness, the The Legacy of Caliban trilogy, and the Space Marine Battles novel The Purging of Kadillus, all by Gavin Thorpe. They also feature in the Horus Heresy novels Descent of Angels and Fallen Angels.Not to be confused with Dark Angel.Also check out the Character sheet.
The Alcatraz: Once you get taken into The Rock, you're not getting out.
Better to Die than Be Killed: With a doomsday virus having been tampered with, and unwilling to sacrifice the planet to escape their base, the squad in Angels of Darkness decide that it would be better to kill themselves than show weakness when their power armor fails to sustain their lives.
Dark Is Not Evil: It is, however, neurotically paranoid about trying to cover up its failings.
Death World: Caliban was not a nice place before it blew up. Mostly due to warp taint and the vicious beasts that resulted from it (at least until the Lion led a crusade to kill them all). These days, the Dark Angels get their recruits from a number of Death Worlds, such as Piscina V.
Energy Weapon: Power swords and plasma weapons are particularly popular among the Dark Angels.
Fantasy Counterpart Culture: The Deathwing used to have some Native American connotations in previous editions, but lately they and the rest of the Chapter have moved more toward a Medieval order of knights.
Heroic Blue Screen of Death: Boreas has such a massive one following his learning that the Chapter never told him about the annihilus, proving that Astelan's claims of Lion El'Jonson's mistrust of the Dark Angels was right, that he nearly kills himself.
Honor Before Reason: The sheer dedication the Dark Angels have to both wiping out all of their traitors and keeping their very existence secret from the Imperium in order to preserve their reputation as noble, honorable, loyal Space Marines means they will do things like abandon critical war objectives to chase after rumors of the Fallen, leave allies to be slaughtered, use their allies as bait or cannon fodder, and murder any Imperial who may have potentially discovered the secret. All of which is causing their reputation to be lost and making the Imperium regard them with just as much distrust and loathing as they fear the revelation of the Fallen's existence will bring.
Ignored Epiphany: After nearly destroying Piscina IV over his obsession with the Fallen, Boreas realizes that the Dark Angels have lost their way, and makes a recording of an impassioned speech begging the Dark Angels to stop being so obsessive over the Fallen. When they arrive to investigate his death, Sammael considers Boreas a heretic for failing to pursue the Fallen.
In Ravenwing the Fifth Company begin developing a rivalry the Ravenwing over deployment, with the Fifth Company feeling that the Ravenwing get the more glorious deployment with the Fifth being placed in a support role. Sammael does have a good reason for deploying the Ravenwing, specifically to hunt for renegade Space Marines, but he can't tell the Fifth that.
More generally, they have a sketchy reputation with other Imperial forces due to their habit of abandoning campaigns mid-battle in order to go and hunt the Fallen. Sometimes, this has lethal results for their erstwhile comrades.
Knight Templar: They tie with the Iron Hands for being the second most fanatical Space Marine Chapter (Black Templars hold the top spot). Boreas nearly destroys Piscina IV over it before he gets a hold of himself.
Meaningful Name: Lion El'Jonson was named after Lionel Johnson, who wrote the poem The Dark Angel.
The Mother Ship: The Tower of Angels, the Dark Angels fortress-monastery from Caliban, survived the planet's destruction due to impressive void shields. It was subsequently repurposed into a mobile fortress-monastery called the Rock.
The Reveal: The Fallen on Piscina IV were after the gene-seed being stored in the Dark Angels basilica, which Nestor was guarding. And they tampered with a virus installed as a fail-safe after the Ork invasion. All of which was kept secret from Boreas.
Screw This, I'm Outta Here!: A rare non-cowardly example, but the Dark Angels and their successors, the Unforgiven, are infamous for buggering off to go and hunt the Fallen at inopportune moments, to the point that some other chapters and Imperial forces actually refuse their assistance rather than risk them leaving at a critical time.
Secret Keeper: The Inner Circle, who keep the secret of the Fallen from their fellow battle-brothers and the galaxy at large.
Shout-Out: The entire Dark Angels legion is one giant in-joke regarding 19th-century poet Lionel Johnson, who wrote the novella "The Dark Angel". Also, The Rock is allegedly named after a gay bar down the street from Games Workshop's original headquarters, as well as a more obvious reference to Alcatraz Island.
Sinister Minister: Interrogator-Chaplains, who are tasked with interrogating Fallen Space Marines to make them atone for their sins... and brutally torturing them to death if they refuse.
Also, Interrogator Asmodai, who firmly believes The Ends Justify The Means. It's believed he doesn't care about "saving the souls of the Fallen" anymore, just collecting more black pearls.
It is hinted that Asmodai has gone off the deep end and is simply a sadist who enjoys inflicting pain; notably, despite his long service, he only has two black pearls for redeeming Fallen - the greatest of Interrogator-Chaplains had 13.
The Spook: The indigenous population of The Rock, the Watchers In The Dark. They are covered head to toe in robes, and have never let anyone see what's underneath. Ever. Games Workshop's official models for them don't have heads, just hollow hoods. Librarians can't probe them because they resist all psychic powers and forms of Warp contact. Are they aliens? Undead spirits of the Fallen forced to serve penance? No one knows.
Treachery Cover Up: Following the rebellion, the Dark Angels have hidden all information regarding the destruction of Caliban and the Fallen's existence. This includes up to and including killing Inquisitors who investigate Caliban's destruction. In Ravenwing it's revealed that the Inner Circle keep a lot of the truth about the Horus Heresy from the rank and file battle-brothers, such as it's existence.
Wham Episode: In Pandorax, Kaldor Draigo lets Azreal know the Grey Knights know about the Fallen, and have known for quite some time. It gets better from there: one of the eight founding Grey Knights was a Dark Angel, and at some point had "switched fates" with Cypher, in turn implying Cypher is a powerful psyker!
Would Hurt a Child: When one of the potential Aspirants balks at the prospect of Nestor opening him up, Boreas takes him aside and explains that if he refused, his family would be shamed. The kid realizes he has to do this, but Boreas says there are no second chances, and calmly snaps the kids neck, leaving him in a room filled with decayed bones, implying that the Dark Angels have been doing this for as long as they've been recruiting from Piscina V.